New sail abbreviations that will be used for IRC from 1st January 2016.
For South (Jun-May certificate year) countries the forms and rules remain as 2015 until 31 May, but note that ALL certificates will show the new abbreviations.

Endorsement: A reminder that this is denoted by the ‘ENDORSED’ stamp at the bottom right of the certificate. Non-endorsed certificates will just have the red IRC Rating Authority stamp. If you need Endorsement for an event you are entering, please contact the Rating Office as soon as possible for advice.

Headsail data: To reflect the fact that not all the headsail measurements are limited by the IRC Rules, we have changed the certificate layout slightly so that some headsail data is shown as *for information. There is no change to the rule, this is simply an administrative update.

Rig Factor: The formula for Rig Factor calculation was developed for 2014 which has resulted in a change in RF for certain rig configurations.

Adjustable mast foot and/or forestay: The words describing moveable mast foot and/or forestay have been updated to reflect the change to treating these two aspects separately

You may be aware of the change to IRC for 2013, with the addition of HUW (headsail upper 7/8 width) and removal of HHB (headsail top width). We would like to assure owners and sailmakers that in the majority of cases this will not mean measurement of existing sails or adverse effect on rating.

The new rule text is:

21.7 Headsails

21.7.1 Headsail area (HSA) shall be calculated from:

HSA = 0.0625*LL*(4*LP + 6*HHW + 3*HTW + 2*HUW + 0.09)

If foot offset is greater than 7.5% of LP, then foot offset shall be declared and foot offset shall be added to LL in the calculation of HSA.

21.7.2 The following shall be declared. LL, LP, HHW, HTW, HUW and LLmax.

21.7.3 HSA, LL, LP, HHW, HTW and HUW of the largest area headsail, and LLmax will be shown on the boat's certificate. HSA and LLmax are the maximum permitted values.

and

HUWThe upper width of the largest area headsail, the upper leech point being the point on the leech equidistant from the head point and the three-quarter leech point.

“So, do I need to have my headsail remeasured?”

For all new sails HUW will need to be supplied (measured by an approved measurer if the certificate is Endorsed).

However, for headsails rated in 2012 a default HUW figure has been set as a percentage of HTW, based on analysis of actual sail data., and will be printed on your revalidation form. Unless you think that the actual measurement is larger than this, you will not need to have your headsail measured.

It will generally only be non-overlapping jibs that may have an HUW larger than the default %, and owners/sailmakers are likely to know when this will apply. Where the actual HUW is larger than default, then of course this must be declared.

“But, surely if my sail’s HUW is smaller than the default, I will be paying for sail area I don’t have?”

We have looked at the effect on TCC of variation in HUW, which for a typical percentage smaller than default would be less than 0.0005. It is therefore considered that for existing sails most owners will NOT need to get their headsail measured, and will not be penalised for this.

“If the difference is so small, why are you bothering?”

Because the effect on TCC is dramatically magnified if in parallel with increasing HUW, LL is also shortened. That is the ‘loophole’ we are fixing.